Teemo's "W" ability is Move Quick. Good ability for run from fight or hunting enemies.

Teemo's "E" ability is Toxic Shot. Your biggest weapon. Here is very important have attack speed more than 1.5 att/s.

Teemo's "R" ability is Nouxious Trap. Cursed and beloved mushrooms. You must stack you Malady debuff to increase damage done by mushroom.

Items

Teemo's items depend on your playing. You can maximize his attack speed and kill champions by Toxic Shots or you can use that my build and make attack speed / lifesteal / damage hybrid killing everythink what he see. Or you can make mushroom dungeon near turrets.

You must have 1) Malady. This item stack enemy magic resistance and make weaker him if he step into your mushrooms. 2) Also you have to buy The Black Cleaver. This item help your team kill enemy faster. 3) Boots. I recommend Berserker's Greavers or Mercury Treads. 4) If you like lifesteal, buy The Bloodthirster. 5) You dont have enough attack speed! Buy Phantom Dancer to increase your attack speed and critical strike. And last item 6) The Infinity's Edge. I recommend this because you have more than 60% critical chance and with The Bloodthirster is ultimate damage and healing item.

Pros / Cons

Laning with Teemo

Teemo's deceptive damage output can be the downfall of his enemies. With not much burst to speak of, many enemies can be lured into a false sense of security. Rushing Phage sets up situations in which, by the time your target realizes he needs to run, it is already too late. Players of Ashe will understand this effect. The enemy stops attacking Teemo and attempts to escape, but it is too late, being slowed and poisoned, the enemy has already lost. Utilizing enemy hesitation is key.

Teemo is a middling solo, but he shines with a good partner. I'll outline the pros and cons of both:

Teemo is a very good asset to have in a side lane. Poison distribution (which I outline later in this guide) allows you to control the creep line. Poison also allows to to greatly harass enemy champions and hamper their farming. His poison in conjunction with exhaust and slows can allow for a quick early kill. His harassment utility can also keep enemy champions off of teammates that usually have difficulty farming (like Rammus)

Soloing middle (or any lane, if a jungler is present) is within Teemo's ability. Teemo is a decent harasser and farmer, and can keep certain carries suppressed during the laning/farming phase. You will SLAP people of average skill around, especially those who become timid after tanking a some damage. Skilled players will give you MUCH more trouble, as they are probably playing heroes better suited to solo and/or beat a solo Teeemo, and they KNOW it.

Unique Skills

Suggested Summoner Spells

My Top Two
Exhaust/Ignite and Ghost. More debuffs and damage for Teemo, plus mobility for defense and offense. Not listing Flash here because of the pending removal. Since the Cleanse nerf, I've found cleanse to be EXTREMELY situational AT BEST, and pretty much not worth taking in 90% of matches.

Other Good Combos
xxx/Flash - Currently Flash is extremely useful at the least, if not imbalanced, being an excellent defensive AND offensive spell. Flash is a great tool for finishing, juking, saving allies with a blind, ect. This is not a flash guide, so I won't list all of the intricacies associated with the spell. Suggested for the newbies who get themselves into trouble more often than not, as the game has started to shift away from flash.

Ignite/Exhaust - Very dangerous if heavy CC is present on other team. Augmented by your masteries, though, makes this combo extremely potent. Blind+Exhaust makes one-on-one fights nasty for most opponents, and the ignite packs a punch and brings additional utility. No escape aids here, though, which hurts squishy Teemo.

xxx/Teleport - With a hefty amount of mushrooms placed at strategic locations, controlling the map can lead to many gank opportunities. You can use teleport to teleport to a mushroom hidden in a bush for a silent ganking opportunity. In most cases, I do not find the added utility of teleport to be more useful than that of other combinations.

Spells I don't like:
Heal is a crutch that for MOST heroes (i.e. non-support/healing/randomness comps) isn't seen past summoner level 15.
Rally is meh, more suited for tank/support champs, if considered at all.
Fortify is meh as well, see above.
Clarity should not be ever needed.
Revive is never an option. Ever.